Field of the Invention
The present invention relates to a prosthesis, particularly a temporo-mandibular joint prosthesis.
Description of the Related Technology
The temporo-mandibular joint in a human body joins the temporal bone of the skull with the mandible bone. The mandible bone may be referred to as the lower jaw bone, which meets the maxilla bone, i.e. the upper jaw, when the jaws are closed. More specifically, in the temporo-mandibular joint, the condyle part of the mandible interfaces with the fossa part of the temporal bone, via an articular disc of fibrocartilagenous tissue.
The temporo-mandibular joint determines movement of the upper and lower jaws, by movement of the mandible bone relative to the temporal bone.
Prostheses for replacing part or all of a temporo-mandibular joint are known. However, it is not straightforward to devise a prosthesis which offers the same or similar functionality as the natural temporo-mandibular joint, so as to provide a joint which for example offers the complex range of motion of the natural joint, an acceptably low risk of dislocation, and a compact joint size.
Known temporo-mandibular joint prostheses use a ball and socket type joint to provide the range of motion; however, this offers a more limited range of motion compared with the natural temporo-mandibular joint.
One known temporo-mandibular joint prosthesis has one joint with a condylar head interfacing with a bearing surface. The form of the bearing surface permits rotational and a translational movement of the condylar head relative to the bearing surface; however, this configuration brings a greater risk of dislocation of the joint.